1. Field of the Invention
The present invention relates to a method of measurement in biological systems and biochemical samples. More particularly, it relates to a method of quantifying molecular mixtures of and adhesions to minute amounts of biological substances or biochemical samples using an accelerator mass spectrometer. Still more particularly, it relates to a method of measurement using intermediate and long-lived radioisotopes bound to small biological substances or biochemical samples which are then converted to forms suitable for analysis by direct isotopic counting using accelerator mass spectrometry.
2. Background of the Invention
Isotopes of various elements have been used in biological processes for some time as a means of tracing, to determine fate and speeds of reaction processes, and for other purposes.
The measurements are made by scintillation counters, autoradiography or other devices which measure the amount of decay of isotopes which have a relatively short half life.
These methods, in general, cannot be used where human beings are involved because of the potential radiation damage from the isotopes and the amount of sample required. At radiation levels which are not harmful to humans, decay counting methods are insufficiently specific and sensitive to give meaningful results. Moreover, the background contamination is high, creating problems for the users of the equipment.